This invention relates to sound barriers, and in particular to sound barriers such as for use along roadways, runways and the like.
A variety of sound barriers for reducing the transmission of the sound of motor vehicles and the like from vehicular paths are known. Such barriers involve the employment of plain walls made of concrete or wood, walls incorporating baffles, louvres channels and cavities, and constructions incorporating sound absorbing materials such as plastic foam, sponge and fibers. The following U.S. Pat. Nos. disclose the preceding types of sound barriers: 3,630,310 (plastic foam), 3,656,576 (fiber), 4,069,768 (hollow channels), 4,094,379 (foamed plastic, fiber, sponge rubber, glass fiber etc.), 4,095,669 (chambers), 4,111,081 (filament mats), 4,156,476 (cavities) and 4,158,401 (cavities). Each of the devices disclosed in the foregoing patents includes complex constructions using very specialized materials which are therefore inherently costly. Moreover, they are of such construction that they would tend to be seriously damaged if struck by a vehicle, leading to expensive repairs of the barrier; and they are not equipped with protective material for the sake of protecting errant vehicles. In fact, there has heretofore not been an effective sound barrier for use along roadways, runways and the like which is inexpensive to manufacture, highly resistant to impact damage, protective to vehicles striking the barrier and effective in use.
Devices known as gabions have been in use for centuries. Gabions are essentially wire cages filled with stone and used as retaining walls along slopes and waterways, revetments for causing the earth to stand at a slope steeper than it normally would assume, drop structures or weirs for retarding water flow velocity to control erosion, spurs, spur dikes and groins for establishing normal water channel width, and channel linings, etc. However, despite the use of gabions since ancient times, gabions have not been used as sound barriers.